Abstract <p>This study assesses recent advances in the preparation and microstructure, oxidation, and hot corrosion properties of diffusion coatings on super alloys for turbine applications. Surface alloying of super alloys by diffusion coating is regarded as an effective method of protecting super alloys against oxidation and hot corrosion degradation. A co-deposition of Pt, Ge, Ta, Ni, Ti, and Ru with a diffusion coating is stated to give outstanding protection against hot corrosion and cyclic oxidation. The review articles start by diffusion coatings, diffusion coating synthesis techniques, various types of diffusion coatings, recent advancements in diffusion coatings, and diffusion coating degradation mechanisms. Diffusion coatings are classified as aluminide, chromide, silicide, boronizing, and nitriding. Pack cementation, chemical vapor deposition (CVD), molten salt bath, and slurry coating process are the several types of diffusion coating synthesis processes. Degradation mechanisms of coatings involve cyclic oxidation, hot corrosion, mixed oxidant corrosion, interdiffusion, and erosion.</p>